The subject of the present disclosure is a method of operation of a gas turbine burning vanadium-contaminated liquid fuel.
The “hot parts” of a gas turbine are components of a gas turbine that are in contact with the combustion gases. In the current models, these combustion gases have speeds of several hundreds of meters per second and temperatures in excess of about 1000° C. The hot parts, are made of superalloys (in general nickel-based) and can be coated with ceramic coatings (anti-corrosion coatings; thermal barriers). Additionally, the hot parts include components of the combustion system (combustion liners; transition pieces etc.) and, downstream in the direction of the flow of the combustion gases, the stationary (“turbine nozzles”) and moving (“buckets”) components of the expansion turbine. These hot parts employ highly elaborate materials and manufacturing processes and are therefore very costly. The “firing temperature” (“T”) is the temperature of the combustion gases entering the expansion turbine. The higher the T, the higher the energy conversion performance of the gas turbine in terms of mechanical or electrical efficiency and power output.
Among the different chemical phases that constitute the ashes of the combustion process, the vanadium pentoxide (V2O5) produced by the oxidation of vanadium in the flames, has a very low melting point (of about 675° C.). The vanadium pentoxide therefore travels as a molten phase in the combustion gases and is capable of causing very intense corrosion at high temperatures of the hot parts, known as vanadic corrosion.